This invention relates to a hydraulic friction heat generator of simplified construction having a plurality of discs with radial slits as the actuators for generating heat. The invention also relates to friction furnaces utilizing the generator; and it also broadly relates to a device for converting rotary motion to thermal energy.
So-called "friction furnaces" typically utilize the friction between stationary and rotating discs to generate heat in a hydraulic fluid for transfer in a heat exchanger. Alternate stationary and rotating discs create certain disadvantages. First, the startup torque may be much higher than the running torque and thus a larger than normal drive motor may be needed during startup but be underused during normal operation. Also, rapid wear may occur on the disc surfaces in close relationship, in spite of a film of oil between them. In addition, very high temperatures may be generated in the film between such discs and cause degradation of the oil. Much of the oil tends to bypass portions of the disc surfaces and be heated by admixture with the small quantity of frictionally heated oil. Thus, while a portion of the oil is subjected to degradive high temperatures, the bulk temperature of the oil is much lower, which decreases efficiency. Also, small losses of fluid in the generator for any reason can cause uncontrolled overheating with accompanying damage unless the disc rotation is immediately halted. Further, the moving and stationary discs of prior arrangements are complex in nature and require costly forging and machining in their manufacture.
Continuous screws or augers or the like when used to generate heat in friction furnaces are unable to create the type of turbulence for the hydraulic fluid that is required for improved heat generation from the energy input.